#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
int a[1010];
int main()
{
	int n;
	cin >> n;
	a[1] = 1;
	a[2] = 3;
	a[3] = 5;
	for (int i = 4; i <= n; i++)
	{
		a[i] = a[i - 1] + a[i - 2];
		a[i] = a[i] % 1000000007;
	}
	if (n == 1)
		cout << a[1] << endl;
	else if (n == 2)
		cout << a[2] << endl;
	else if (n == 3)
		cout << a[3] << endl;
	else
		cout << a[n] << endl;
	return 0;
}